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(No Model.) 2 Sheets--Sheet I.

. J. RAPIEPP. METHOD OE-EINDING THE RANGE 0E DISTANT OBJECTS.

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(No Moae1.)l 2 sheets-sheet 2.

J. RAPIEFF. METHOD 0E FINDING THE RANGE 0E DISTANT OBJECTS.

No. 441,974. Patented Dec. 2, 1890.

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UNITED STATES PATENT OFFICE.

JOIIN RAPIEFF, OF NEV' YORK, N. Y.

METHOD OF FINDING THE RANGE OF DISTANT OBJECTS.

SPECIFICATION forming part of Letters Patent No. 441,974, dated December2, 1890.

Application filed March 10, 1890. Serial No. 343,362. (No model.)

To @ZZ whom it may concern,.- uniform resisting conduetibi'lity, afractional Be it known that l, JOHN RAPIEFF, a .subportion ot which isincluded in an electric ject of the Czar of Russia, residing in thecircuit, such fractional portion bearing in city, county, and State of New York, have inlength, as B C, a ratio to the variable base D 55 5vented certainnew and useful Improvements E ot the triangle D A E,included between in Methods of Finding the Range ot' Distant the linesof sight D A and E A directed upon Objects, of which the following is aspeciticathe distant object A. The electrical resisttion. l ance of theconductor B C, thus variable in My invention relates to determining thepredetermined relation to the base of the tri- 6o [c range of a distantobject and givingthe indiangle` maybe measured in the followingmancations at distant locations from the rangener: The conductor B C isincluded in 'a finding instrument. 1 l branch a ot a circuit of thebattery H. A My invention is applicable to alidade-arms`compensating#indicator I is included in a or telescopes operated uponfixed angles ot branch b of the battery I-l. 65 I5 triangulation, beingmovable with relation to J representsagalvanometer, the indicating eachother upon a variable base-line, as illusneedle of which is balancedwhen the curtrated in my patent application, Serial N o. rents are equalin the branches d and l), or 294,397, tiled December 22, 1889.unbalanced when such currents are dideren- My invention consists indetermining a tial. The contact at Cof the `iiexible. wire a' 7o 2ofractional portion of an electrical conducting is moved correspondinglywith the movement body, which fractional portion bears in length of thetelescope or alidade E being attached a ratio to the variable base ofthe triangle inthereto, while the connection at B of the wire eludedbetween two lines of sight directed a remains fixed. upon a distantobject and said base-line and K is a resisting-conductor, over which the75 25 in measuring the electrical resistance of the index/1' novesinelectrical contact. The pivot said length. of the index t' iselectrically connected by the In the drawings, in which similar lettersof wire b with the battery I-l. The index t is reference indicate likeparts throughout, provided with a graduated dial,asindicated, Figure lis an electrical diagram showing from which readings corresponding withlin- 8o 3o symbolically and in one form the essentialealmeasurements-such asDAor D'A-may elements of my invention, and Fig. 2a simibe obtained. The galvauometer, the battery, lar diagram showingcertain practical modiand the dial I are assumed to be stationed at aiications thereof. distance from. the instrument D E and its Let A, Fig.l, represent the objective point, resistance-wire B C being undercontrol of an 8 5 3 5 the distance of which is to be determined.independent observer.

D represents an alidade or telescope, which As illustrated in Fig. 2, Imay employ a teleis rst directed upon the object A. phonic receiver J inconnection with an in- E represents a telescope or alidade, theduction-coil J2, in lien of a galvanometer, an axis of which maintains aconstant angle A interrupter nl. being introduced whereby 9o 4o E D tothe axis of the telescope or alidade D sound vibrations are eii'ected.In this the While movable to and fro upon the bar F, balancing of thetwo branches a b of the cirfixed perpendicularly to the telescope oralicuit will cause the sounds due to circuit indade D. The angle D A Eof the triangle is terruptions to subside entirely in the telethusrendered constant, the base D E thereof phone J. Furthermore, in lieu ofthe fiexi- 95 45 being the variable element by which the perble wireCt', I may employ parallel wires B C pendicular D A of the triangle ismeasured B2 C2, upon which a contact C3 completes the when the movabletelescope or alidade is circuit, multiplying the variation ofresistbrought into line at E with the object A, for ance for a givenmovement. instance, or at E with the object A', as indi- In operation,the telescope or alidade D beroo 5o cated by dotted lines. ing rstsighted upon the distant object A, B C represent an electrical conductorof the telescope or alidadc E is moved upon the bar F until its axisalso coincides with the said object. An observer stationed at a distanceby noting the galvanometer J or equivalent and adjusting the resistanceK may determine the resistance in the conductor B C, equilibriating anyposition of the contact C thereon. The reading of' the distance-such asD A-is then obtained from the dial I. It will be seen that by employinga plurality of conductors at B C and a single conductor I the linealspace of the readings may be ampliied.

The herein-described instru mentalities may be modified in Various ways,such as Ihave illustrated and described in a separate application,Serial No. 303,140, filed March 13, 1889.

I am aware that dierential actions as exhibited between two branches ofa circuit have been employed hitherto in making measurements, and Itherefore do not claim the same as a part of myinvention. Neither do Iclaim the improvement in the art of Vfinding the range of a distantobject which consists in rst determining a fractional portion of aconducting-body bearing in length a ratio to the angle included betweentwo lines of sight directed upon a distant object and, second,

measuring the electrical resistance of said length, as I am not thefirst inventor thereof; but

What I do claim, and desire to secure by Letters Patent, is

l. The method of finding Y the range of a distant object, which consistsin first determining a fractional portion of an electrical conductingbody, which fractional portion bears in length a ratio to the variablebase of a triangle included between two lines of sight converging at aconstant angle upon a distant object, and, second, measuring theelectrical resistance of said length.

2. The method of measuring a variable base of a triangle includedbetween two lines of sight converging at a ,permanent angle upon adistant object, which consists in first in cluding a fractional portionof a conducting body bearing in length a ratio to the said base in anelectric circuit or branch of a circuit, and, second, equalizing theresistance of another circuit or branch of a circuit with the rst, thesaid equalization being interpreted by units of lineal measurement.

JOHN RAPIEFF. Witnesses:

OHAs. W. FORBES, C HAs. HANIMANN.

